Add data-driven public pages (home, news, profile)

Real App Router pages reading the converted Prisma models:
- home: latest 4 articles (websiteArticles) + hotel_name from settings
- /news + /news/[slug]: article index and detail
- /u/[username]: profile (avatar via imager helper, motto, rank, credits, online)
- shared SiteNav (reads session via auth() + hotel_name), globals.css
- src/lib/format.ts: avatarImageUrl + excerpt helpers (unit-tested)

Verified: tsc exit 0, vitest 43/43, next build exit 0 (7 routes). Pages render
against a live DB (deferred until DATABASE_URL is provided). i18n to be layered
on next.

src/lib/format.ts

@@ -0,0 +1,21 @@
+/** Build a Habbo avatar-imager URL for a figure string. */
+export function avatarImageUrl(
+  base: string,
+  look: string,
+  opts: { size?: "s" | "m" | "l"; headOnly?: boolean; direction?: number } = {},
+): string {
+  const params = new URLSearchParams({ figure: look });
+  if (opts.size) params.set("size", opts.size);
+  if (opts.headOnly) params.set("headonly", "1");
+  if (opts.direction !== undefined) params.set("direction", String(opts.direction));
+  const sep = base.includes("?") ? "&" : "?";
+  return `${base}${sep}${params.toString()}`;
+}
+
+/** Trim text to `max` chars on a word boundary, adding an ellipsis. */
+export function excerpt(text: string, max = 160): string {
+  if (text.length <= max) return text;
+  const cut = text.slice(0, max);
+  const lastSpace = cut.lastIndexOf(" ");
+  return `${(lastSpace > 0 ? cut.slice(0, lastSpace) : cut).trimEnd()}…`;
+}